o Removed features (directory authorities):

    - Directory authorities no longer advertise or support consensus
      methods 1 through 12 inclusive. These consensus methods were
      obsolete and/or insecure: maintaining the ability to support them
      served no good purpose. Implements part of proposal 215;
      closes ticket 10163.

  o Minor features (directory authorities)
    - If a directory authority can't find a best consensus method in the
      votes that it holds, it now falls back to its favorite consensus
      method. Previously, it fell back to method 1.  Neither of these is
      likely to get enough signatures, but "fall back to favorite"
      doesn't require us to maintain support an obsolete consensus
      method. Implements another part of proposal 215.